Disable the background responsiveness timer when RunningBoard is used. We used to only disable it on iOS because we only used RunningBoard on iOS. However, now that we use RunningBoard on macOS too, we should disable it on this platform too. Background processes now get a very low priority and eventually get suspended. This would cause false reports of unresponsive processes.
Pull request: https://github.com/WebKit/WebKit/pull/15306
Committed 265536@main (4224c4b333f8): <https://commits.webkit.org/265536@main> Reviewed commits have been landed. Closing PR #15306 and removing active labels.
<rdar://problem/111368716>